Germanwings Co-Pilot Andreas Lubitz Tried Controlled Descent on Previous Flight: French Investigators

Andreas Lubitz sent earlier plane into a descent, then brought it back up again.

"At 7 h 20 min 50, the selected altitude decreased to 100 ft for three seconds and then increased to the maximum value of 49,000 ft and stabilized again at 35,000 ft," the report details. "From 7 h 22 min 27, the selected altitude was 100 feet most of the time and changed several times until it stabilized at 25,000 ft at 7 h 24 min 13."

Another similarity between the two flights is that on both occasions the pilot left the cockpit for a few minutes, leaving the co-pilot in command of the controls.

The BEA notes that this report is the first of several and says it will pursue looking into "systemic failings that may have led to this accident or similar events."

Authorities will seek to understand the compromises made between “the requirements of security, specifically those that followed the attacks on 11 September 2001.”